The Supreme Court won't hear a Maryland man's argument that the Second Amendment allows him to carry a gun outside of his home for self-defense.

The high court on Monday refused to hear an appeal from Charles F. Williams Jr., who was arrested in 2007 for having his legally-purchased handgun outside his home without a state permit.

The high court has ruled there is a right to keep a gun in the home for protection. But gun advocates say people also have the constitutional right to carry their guns outside the house for self-protection.

Maryland courts say if the Supreme Court agrees with that theory "it will need to say so more plainly." The high court refused the opportunity on Monday.